/**   
 * 显示遮罩   
 */   
function showMask(){    
      var divMask = document.getElementById('divMask');
      divMask.style.visibility = "visible";    
      divMask.style.backgroundColor = '#333333';    
      divMask.style.filter = 'progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=50,finishOpacity=50);';//'alpha(opacity = 60)';    
      divMask.style.opacity = '0.5';    
      divMask.style.left = '0px';     
      divMask.style.position = 'absolute';    
      divMask.style.top = '0px';
          
      resizeMask();    
      window.onresize = resizeMask;    
}    
   
/**   
 * 关闭遮罩   
 */   
function closeMask()    
{     var divMask = document.getElementById('divMask');    
      divMask.style.width = "0px";    
      divMask.style.height = "0px";    
      window.onresize = null;    
}    
   
function resizeMask()    
{     var divMask = document.getElementById('divMask');    
      divMask.style.width = document.body.scrollWidth;    
      divMask.style.height = document.body.scrollHeight;    
   
}  
